Actuator

An actuator comprising:

• a stator having a circular cylindrical shape;
• a movable shaft inserted inside the stator and configured to reciprocate in an axial direction;
• and
• a movable element having a circular cylindrical shape and being provided inside the stator and integrally attached to the movable shaft, wherein
• the stator includes
• a stator main body having a circular cylindrical shape,
• an outside yoke being structured with a magnetic material, having a circular cylindrical shape, and accommodating the stator main body therein, and
• a first stopper and a second stopper being structured with a magnetic material and configured to close openings located at opposite ends of the outside yoke,
• the stator main body includes
• an inside yoke being structured with a magnetic material, having an annular shape, facing the movable element in a radial direction and being arranged so as to surround an outer circumference in a central part, in the axial direction, of the movable element,
• a permanent magnet having an annular shape and being attached to an outer circumference of the inside yoke,
• a stator frame having a circular cylindrical shape, including a bobbin which is provided on at least one side, in the axial direction, of the inside yoke and the permanent magnet and around which a coil is wound, and being configured to support the inside yoke and the permanent magnet, and
• the coil wound around the bobbin of the stator frame,
• the first stopper includes a first projection part having a circular cylindrical shape and projecting from a central area toward the second stopper, and has a first hole part through which the movable shaft is inserted at a center of the first stopper,
• the second stopper includes a second projection part having a circular cylindrical shape and projecting from a central area toward the first stopper, and has a second hole part through which the movable shaft is inserted at a center of the second stopper,
• the first projection part and the second projection part are fitted in opposite end portions, in the axial direction, of the stator frame,
• the movable element is disposed between the first projection part and the second projection part, and
• attached to the first hole part and the second hole part are bearings that support the movable shaft so as to capable of reciprocating.